Once Burned, Twice Shy
by Julia451
Summary: "He would never make that mistake again." Fool me once, shame on you; fool me twice, shame on me. What if part of the reason Hiccup decided not to trust Dagur was that he couldn't forget what happened the last time he'd trusted an enemy? One-shot centered on Mildew's betrayal in "Defenders of Berk" and Dagur's arc in Season 3 of "Race to the Edge."


"Haven't seen you this low since the night you shot down that Night Fury."

Hiccup looked up in surprise – he hadn't realized where he was. He walked listlessly over to Gobber's stall, Toothless by his side. Gobber frowned at the sight (seeing Hiccup walk when he could have flown was never a good sign).

Hiccup lightly rested his right arm on his dragon's head, unable to look his old mentor in the eye. "You heard the news?"

"Stoick filled us all in," Gobber said flatly.

"How could I let this happen?" Hiccup wondered with a sigh.

"Knew I should have knocked his head off when I had the chance."

"Next time, don't let me stop you."

"Don't be too hard on yourself. The old coot made us all believe he'd changed."

"That's what my dad said."

"Because it's true." Gobber paused to sigh and frown in disgust at their former tribesman. "We all should have known better than to trust that old weasel."

 _You did_ , Hiccup thought to himself. _You knew he couldn't be trusted. Until you listened to me. If it hadn't been for me, none of this would have happened. I should have known... I should have figured it out... I shouldn't have fallen for it..._

Ever since the riders had returned from rescuing Meatlug from the Outcasts, Hiccup had only been able to think of one thing – not Meatlug's narrow escape, not how useful the Terrible Terrors had proven to be, what else they could train them to do, the threat they now knew the Whispering Death tunnels posed to the island, how to fix that vulnerability, or what Alvin's next plan might be... No, now that they were all safe and the Outcasts were gone, all he could think about was what they'd learned today about Mildew, the man whom Hiccup, up until a few hours ago, thought had saved his life. Until he saw Mildew try to help the Outcasts stop the riders from rescuing their dragon.

It had all been an act. Mildew wasn't the Outcasts' prisoner. He was still their spy. There was no denying it – anyone could tell from the way he'd acted today. Which meant, on that day back on Outcast Island before Bork Week, Hiccup hadn't given a reformed enemy a chance to redeem himself – he'd walked right into a trap with his eyes wide open.

Hiccup had done _a lot_ of embarrassing things in his life, but he had never felt as ashamed of himself as he did right now. Had he really been _that_ naïve? How could he have believed all that nonsense about wanting to make things up to him? Mildew had handed him over to the Outcasts, but all he had to do to get Hiccup to trust him was essentially say, "I'm sorry, I've changed," and Hiccup had accepted it! What had he been thinking?! How could he have been so gullible?! Alvin had everything he needed, knew everything he needed to know, to destroy Berk, all because Hiccup had been stupid enough to trust someone who had always been his enemy!

Hiccup was pulled out of his thoughts when he heard Gobber say, "You can't let it get to you."

"I let him trick me," Hiccup said flatly. Toothless, sensing his distress, pressed his head closer to him, trying to offer his support.

"Torturing yourself is not going to change that," Gobber said in the same patient but firm tone he'd used when first teaching his young apprentice how to work the forge. "You made a mistake, Hiccup – no one's going to deny that. But a true warrior doesn't let his mistakes control him – he learns from them. You know the old saying: 'Fool me once, shame on you – fool me twice...' "

Hiccup finished it for him: "... shame on me."

"Exactly. The bad news is, Mildew tricked you, and you fell for it. The good news is, you'll never fall for that trick again."

No doubt of that. Hiccup raised his head, suddenly feeling strengthened by the thought. "That, I can definitely promise you." He didn't know what would happen next or how this would play out or how he would make this right, but one thing he knew for sure was that he would _never_ make that mistake again.

Hiccup tried to take Gobber's advice and not dwell on how badly he'd messed up, but it wasn't easy. He couldn't forgive himself for not spotting what should have been such an obvious set up. Fortunately, whenever it started to get to him, Hiccup was able to snap himself out of it by reminding himself of his vow – he'd never fall for that trick again. That thought got him through every attack of guilt and shame for letting himself be duped so easily. It kept him calm and gave him strength. He repeated it to himself constantly over the next few months whenever he needed to push aside the memories of that day: _I'll never let it happen again. That act will never work on me again. No one can fool me like that anymore_.

Hiccup started to recover after he defeated Dagur and peace was declared with the Outcasts. Once he knew no one would get hurt because of his stupidity, that his foolishness couldn't cause any more damage, he no longer felt obligated to keep punishing himself. Plus, he had helped save his father, get rid of the Screaming Death Mildew had planted on Berk, and form the alliance with Alvin – surely that was enough to make up for his failure against Mildew and Alvin months ago. He felt like he had redeemed himself and regained his honor – the code all Vikings lived by would say he had.

He had won. Mildew managed to outsmart him once, but it did him no good. Mildew may have won one round, but he lost the game. After all his plotting and treachery, he'd accomplished nothing and lost everything. Hiccup, the dragons, and Berk were beyond his reach. The fact that he'd beaten Hiccup in the beginning wasn't important – in the end, all his plans for revenge against Hiccup had failed, and that was all that mattered. It was a victory Hiccup had to let himself savor.

By the time Mildew was tried for his crimes and banished, Hiccup had stopped feeling guilty about falling for his trick. Soon after that, he stopped thinking about it entirely. He hadn't forgotten it, it was stored in the back of his mind with his other memories, but it wasn't important. He wasn't proud of what he'd done, but he wasn't haunted by it. Whenever something happened to remind him of it, he could think of it without getting too angry at himself. He'd made plenty of mistakes when he was young – that one no longer mattered to him. He'd learned his lesson. He was able to put it behind him.

It was over. Hiccup didn't have many reasons to think of it during three years of relative peace and boredom. After Dagur escaped, he had much more important things on his mind. At first, all his attention was focused on finding and capturing Dagur. Before long, his primary concern was stopping the dragon hunters. That led to him becoming obsessed with outsmarting Viggo Grimborn. Eventually, he made a far bigger, costlier, more inexcusable, more frustrating mistake – worse, it seemed, than any he'd made in his life.

Losing the Dragon Eye because he'd let Viggo outwit him was unbearable. Had Hiccup thought about it, trusting the wrong person once when he was a kid would have seemed like nothing in comparison, but he didn't think of it. That was the last thing on his mind throughout all the months they lived on Dragon's Edge fighting the hunters. After the Viggo fiasco, he had little time to care about anything except finding his new enemy and getting back the Dragon Eye.

The day a routine scouting mission went horribly wrong, it had been months, if not years, since Hiccup had thought of his day in that Outcast prison cell. His only concern at the time was protecting Toothless. When he realized Dagur was the one defending him from the dragon hunters, he was as shocked and confused as he'd been the day he found the Berserker chief on Dragon Island.

When Dagur offered to get Toothless somewhere safe, Hiccup had no intention of accepting. It didn't make sense – why would someone who had tried time and again to kill them be so keen on helping them now? Only the desperateness of the situation forced Hiccup to decide the risk was worth it – he accepted Dagur's help without trusting him.

Dagur's insistence that he would have hurt them at the beginning if that was his goal didn't change Hiccup's mind at all. Dagur had tricked him more than enough times to make Hiccup doubt his word now. His excuse for what he was doing here and why he was acting so unlike the deranged lunatic Hiccup had known all his life didn't help. Dagur had always been crazy and crafty – Hiccup had every reason to doubt his story, which Dagur himself didn't deny.

Dagur handing him a sword before they left, however, at first caused Hiccup to consider it might be safe to drop his guard a little, but some instinct warned him it was too dangerous. Hiccup didn't question the impulse or where it came from; he just obeyed it. Still, he was then open enough to the possibility that Dagur had genuinely turned his back on his old goals and allies to ask what had caused the "new Dagur." His explanation made sense, but Hiccup still didn't feel confident enough to fully believe it. In fact, some voice in his head scolded him for even starting to believe it at all, telling him he was out of his mind. Hiccup agreed but simply felt like he had no choice. So he went along with his old enemy's plan while remaining on the lookout for the inevitable double-cross.

One thing Hiccup was certain of was that, as a friend or a foe, he was safer with Dagur than he was with an army of dragon hunters. Hence why Hiccup warned him when he saw a hunter about to sneak up on him during the skirmish that broke out. Hiccup was surprised when he saw how much effort Dagur put into successfully resisting the urge to kill his opponent. The old Dagur would have killed him without hesitation; if his new self was an act, he wouldn't pretend to need to restrain himself – he would just pretend to spare the man, no effort needed. Why would he act like keeping himself from killing his attacker was so difficult unless... he genuinely didn't want to be that raging, bloodthirsty killer anymore? The sight made Hiccup inclined to believe it wasn't an act, but something inside him refused to let him show it. Why? Why couldn't he trust him?

Hiccup got his answer when Dagur said, "I told you, I've changed." Hiccup's first thought was, _Yeah, I've heard that before_. He was about to say it when Dagur threw him to the ground so he could take an arrow to the shoulder for him, forcing his thoughts to a grinding halt. Not until after Hiccup had taken out the last hunter and gotten his unconscious ally back to the waterfall was he able to resume his thoughts.

" _I told you, I've changed."_ Yes, Hiccup _had_ heard that before... different words, but the same plea... three years ago... from another enemy who'd claimed to regret his actions and offered to help him, promising he could trust him.

It was the first time in months, maybe years, that Hiccup had consciously thought of that incident. Why didn't he see it before? Here he was in the exact same position he'd been in that day on Outcast Island! The memories came rushing back: his escape from the prison, his discovery of the betrayal, his promise never to let anyone trick him like that again – the mantra he had repeated to himself so many times that it had become second-nature. He may owe Dagur his life now, and he'd paid that debt by saving his, but he _couldn't_ trust him. He would never be able to forgive himself if let his enemy fool him again.

Of course, Hiccup knew he'd been insane to trust Dagur even this much, but it was either that or let the hunters capture him and Toothless. At least Dagur couldn't pose much of a threat at the moment, Hiccup thought as he tended to his wound, relieved he didn't regain consciousness. Maybe he and Toothless could get away before he came around, but, no, his dragon was still in no condition to fly. They were trapped here until the effects of the dragon root wore off... unless Hiccup gave him the cure...

The voice that had been warning Hiccup to stay on his guard all day viciously berated him for even considering such a thing. Who was the deranged one here? He couldn't believe anything Dagur said, including this supposed antidote made from a relative of lethal dragon poison!

But Dagur had never wanted to kill Toothless – he wanted Hiccup's dragon for himself... Maybe he wasn't working for himself – he hadn't been last time they'd seen him... But the hunters wanted the Night Fury alive, too... Maybe they'd decided, if they couldn't have him, it was better to eliminate such a powerful threat... Then why not just let the dragon root do it? Why concoct such an elaborate trap...? To try to gain his trust... Was almost getting killed by an arrow part of the plan? The unconsciousness clearly wasn't an act. Those were pretty extreme measures for Dagur to go to just to convince Hiccup to trust him...

 _It doesn't matter!_ the other side of Hiccup's mind warned him. _You can't trust him! Don't make that mistake again!_

Things are different this time, Hiccup insisted. Dagur and anyone he could possibly work for had always wanted Toothless alive. Dagur had risked his life at least twice today to save Hiccup's. If he was planning something against them, it clearly required keeping them alive, so he wouldn't have tricked Hiccup into poisoning Toothless. In spite of his conclusion, the voice kept ordering Hiccup not to do it. The sight of his sick dragon overruled it – Hiccup ignored his most powerful instinct and made the antidote.

By the time the medicine was ready, however, his resolve had weakened; even when it looked finished, Hiccup couldn't bring himself to give it to his dragon. If Dagur hadn't woken up, he was sure he never would have given it to him. He had to keep telling himself that, no matter what Dagur was lying about, his goal wouldn't be to kill Toothless. When it looked like that was indeed what was happening, Hiccup completely lost control. He attacked Dagur, not because he was angry at _him_ , but at himself. How could he have been so stupid?! Hadn't he learned anything three years ago?!

Hiccup truly didn't care at that point if the dragon hunters killed him – it was no less than he deserved. He thought about telling them their target was dead by now but figured they wouldn't believe him. He was hoping Astrid would be able to track down Dagur and make him pay for this when he heard Toothless coming to his rescue. He almost couldn't believe his eyes when he saw his best friend was alive and well and strong. He was too overjoyed at the sight to wonder what it said about Dagur. That must have been why, after Dagur saved him (again), Hiccup shook his hand as if they were old friends. It was a reflex; it felt right. The reminder not to trust him didn't come until after the subsequent battle was over and Hiccup couldn't find him anywhere.

Where was he going? Had he learned anything today that would help him attack the dragon riders? No – unlike last time, Hiccup hadn't revealed any secrets (not that Dagur had shown any interest in learning any... clever strategy). Besides, Dagur had gotten Toothless – if Dagur had been plotting with the dragon hunters today, he wouldn't have given that up. Nothing the hunters could possibly gain from tricking Hiccup into trusting Dagur would have been worth losing the Night Fury. Dagur couldn't be working with the dragon hunters anymore – that part of his story, at least, must be true.

That didn't mean Hiccup trusted him. If Dagur was out for revenge against Viggo, well, maybe that could benefit the dragon riders in the long run, but it didn't mean the riders, their dragons, Heather, or Berk were safe from him. He was still their enemy, even if he was the hunters' enemy now, too. Hiccup couldn't trust him...

So why did Toothless? "Never thought I'd see that, bud," Hiccup mused aloud as they flew home. "Dagur flying you? How did that happen? How did he get _you_ to let him ride you?" He knew the answer to that, sort of. "I know, so you could come save me." Toothless would have been able to hear he was in danger, wanted to fly to his rescue, and realized Dagur was the only human around that could help him get there. "But how did you know he would help us? He's always been our enemy – you know that. So why did you trust him now?"

Of course, most dragons could sense when you were trying to help them – had Dagur helping Toothless escape the hunters and hiding him in his cave convinced the Night Fury he was a friend now? Maybe Toothless had even figured out he was responsible for the medicine that had made him feel better. But Toothless was always hostile towards anyone who threatened or even appeared to threaten Hiccup, and Hiccup had treated Dagur like a threat the entire time... hadn't he? Hiccup started to wonder, was he considering trusting Dagur because Toothless had trusted him... or did Toothless trust Dagur because he'd sensed that Hiccup already trusted him...?

The image of Gobber releasing Mildew when Hiccup assured him "I owe Mildew my life" interrupted the thought. It didn't matter how grateful Hiccup or Toothless felt towards Dagur for helping them today – he'd always been their enemy, and it was too dangerous to think he'd changed now. Hiccup couldn't make that mistake again...

Now that their little misadventure was over, Hiccup put the Dagur mystery out of his mind. As the weeks went by, he began to think the issue would never come up again. Coming home to find Dagur casually hanging out in his room was the last thing he expected. If only he'd been more prepared, maybe he could have thought of a way to get rid of him without anyone knowing he was there and without Dagur learning Heather was there, but his mind was too preoccupied with the plans to attack the shipyard to think of any solution other than giving him what he wanted.

Hiccup spent the next few hours trying to think of a way out of it. He couldn't teach Dagur how to train dragons! That was _exactly_ what Mildew had tricked him into doing over three years ago! This was looking more and more like the situation he'd been in that day – did he want it to end the same way, too? Dagur was an even more dangerous enemy than Mildew or Alvin...

Exactly! This time, Hiccup knew he was dealing with an enemy – he could take the necessary precautions, like give him the most harmless dragon he could think of... Even as he formed the plan, Hiccup knew it was irrational. If he thought Dagur was a threat, why did he care about his friends finding him? Why not lock him up and send him back to Berk or Outcast Island as a prisoner? But if Hiccup did that to the person who'd saved his life, _he_ would be the traitor.

But even if Hiccup couldn't treat Dagur like a common criminal, why hide that he was here? Heather would make it clear she wanted nothing to do with him, and so would the other riders. If he proved to still be dangerous, Hiccup could lock him up without feeling guilty; if he had really changed, he would leave...

 _If?_ How could he even think that? If Hiccup continued to think of Dagur as a possible friend, that there was even a chance they could trust him, he would end up putting his whole team in danger. If he let himself head down that road again, it would only lead to disaster just like before. He couldn't let this happen again... He had to get Dagur off the island as soon as possible with as little trouble as possible – teaching him to ride a dragon was the easiest way to do that. Hiccup would just have to make sure he didn't show him anything that could be used against them later.

In a way, Hiccup was glad his friends learned what he was hiding – arguing with real people was much easier than arguing with yourself. Now one side would outnumber the other. Astrid took the side he'd expected, repeating all the arguments he'd been giving himself since Dagur had first shown up in that cave. So why didn't she make him feel any more confident he was right not to trust Dagur? Instead of letting her talk him into doing what he should have done yesterday, Hiccup kept defending him. Not that it made any difference. Nothing Hiccup or Dagur said made Astrid much more willing to trust him – she just believed he was safe enough to keep around until they could get rid of him without causing trouble.

Heather's early return quickly put an end to that plan. The voice in his mind that had been speaking against Dagur all day told Hiccup he shouldn't care how unhappy his sister's treatment made him, but Hiccup couldn't help it. You didn't have to trust someone to feel sorry for them. He couldn't trust Dagur with their secrets or their safety, but he could care what happened to him. He couldn't forget what he had done in the past, but he could forgive him – what was the harm in that?

So Hiccup didn't resist the empathy he felt rise up when he saw Heather disown her brother. It felt strange, watching the scene from this angle, but no less painful than the day his father had done pretty much the same to him. He didn't know what he was planning to do when he followed Dagur. Tell him she'd come around? (Which would be a lie.) Tell him he knew how he felt? (Which would mean nothing.) Ask him not to go berserk and use this as an excuse to fight the riders again...?

Well, whatever he'd wanted to say, Hiccup never got the chance, because as soon as he saw Dagur, all his sympathy and compassion was swallowed up by suspicion and anger. Dagur had asked Hiccup to trust him before, but he had never acted like Hiccup was an idiot for not believing what he said until now. Hearing Dagur challenge his judgment instantly put Hiccup fully on the defensive with no opposing voice second-guessing himself. It was time to make a decision once and for all. Their entire plan depended on his choice – could he trust Dagur or not?

Dagur's doubts about the shipyard attack were understandable. If he wasn't working for the dragon hunters anymore, he had no reason to talk them out of it. He had saved Hiccup and his dragon. Toothless felt safe enough with him to let him ride him. He'd passed up numerous chances to hurt all of them. He looked genuinely heartbroken when Heather rejected him. He insisted he'd changed...

So had Mildew. Hiccup had vowed he wouldn't let himself be tricked like this again; in the end, that was what carried the day. He may have been young and naïve when he'd trusted Mildew, but he knew better now. Why should Dagur be any different? He was using the exact same strategy – trying to make Hiccup feel sorry for him, pretending he'd seen the error of his ways and was trying to make it up to him, asking for a second chance. It was too late. There was no way Dagur would ever get Hiccup to trust him. That trick only worked once. Hiccup had learned his lesson. He would never make that mistake again...

* * *

It turned out, he didn't make _that_ mistake. Not this time...

* * *

It was about a week later that Hiccup went with Heather to gather greens. Since they had never picked anything from this area before, Heather warned him to be careful. Hiccup began with a patch of safe and familiar goatweed, but his mind was far away from the task. When he finished, he moved on and reached for another plant but caught himself just in time and quickly jerked his hand away at the last second.

Heather noticed and, wondering if something dangerous or poisonous had nearly bitten him, came over. "What's wrong?"

"Fire fern," Hiccup said indifferently, already moving on. "Burns when you touch it."

Heather look at the plant for a second. "No, it's not." Hiccup stopped and turned around. "It's sun fern. They do look a lot alike at first glance, but see – the leaves are broader and a lighter shade of red, and it has a fainter but sweeter scent. Perfectly safe."

"Oh," Hiccup said as Heather cut off several handfuls of leaves and dropped them in her basket. "I thought it was the same."

"Guessing you learned the hard way not touch fire fern."

"Yeah, that's something you don't forget..." Hiccup's voice trailed off awkwardly as he was forced to remember who had first shown it to him.

"You just have to look closely," Heather said as she stood up, then went back to work.

Not feeling very concerned about food at the moment, Hiccup sat down on a rock. Toothless bounded over to him, and Hiccup stroked his head while, against his will, the rest of the events of that day replayed in his head. In hindsight, he was able to see that Dagur hadn't been begging for help but only trying to help _them_ with nothing to gain, that he never tried to goad Hiccup into forgetting the past and blindly trusting him but acknowledged he didn't deserve it, that he never tried to make Hiccup feel sorry for him... unlike how someone else had acted when trying to trick him.

 _Why didn't I see it?_ Why did someone have to give his life for him to prove he was a friend? It shouldn't have come to that. He'd wanted to trust Dagur since the moment Toothless had let him ride him – why had he kept pulling himself back?

Instantly, he heard the answer: _Because you couldn't afford to make that mistake again_.

Grunting in helpless frustration, Hiccup slammed his fist into the rock, wishing it hurt more than it did. It had been over three years. He was just a kid. He thought he'd put that incident behind him. He thought it was over. He never realized how badly it still haunted him. He never knew, after all this time, it would lead to something like this.

He wondered if Mildew would be happy to know he had helped kill his former chief, one of Hiccup's bravest friends. _Congratulations_ , Hiccup told him in his mind. _You win. You got your revenge after all_.


End file.
